Nothing about the sweet n sour sauce they use there has ever really leapt out at me as especially different from SnS I've had elsewhere, I imagine they're using standard issue Chinese takeout industry sauce. I haven't had especially great luck replicating it in my home kitchen, but Plum Sauce or Duck Sauce from the Asian market cut with a bit of seasoned rice vinegar and a dash of soy sauce and freshly grated ginger scratches the itch well enough.

That looks like pulled pork on there - is it? Pineapple would be a good foil to that. You can do a pretty solid oven cooked version of that if you need to (I'm kind of a heretic as I don't really think pork is best served smoked and barbecued).